A clinical investigation trial to analyze the feasibility of the intraperitoneal therapy of using activated monocytes of peritoneal carcinomatosis with colorectal carcinoma has been designed. This trial is testing the toxicity of activated monocytes given carcinomatosis. The first six patients received autologous lymphocytes infused intraperiotoneally and preactivated at a dose of 1,000 units/ml of gamma interferon. The seventh patient is receiving similarly activated monocytes but is also receiving 2,000 cc of impersol supplemented with gamma interferon at a dose of 1,000 units/ml given intraperitoneally on a daily basis. The toxicities to date have been Tenchkoff catheter related problems with three patients with three patients needing replacement of occluded catheters and three episodes of bacterial peritonotis which resolved with antibiotic therapy. In addition, the patients have noticed variable degrees of abdominal pain 4 hours after the infusion of monocytes and lasting approximately 12 hours. Although response rates cannot be determined from this study, 3 of 6 evaluable patients were without evidence of disease at the completion of their second-look surgery.